The invention relates to an apparatus or instrument for ligating lesions such as for ligating mucosal and submucosal lesions within a hollow organ of the body, such as the alimentary tract. More particularly, the invention relates to an apparatus adapted for use in conjunction with an endoscope.
The endoscopic treatment of lesions presently encompasses a variety of techniques such as electrocauterization, laser photocoagulation, heat therapy by the application of heat probes, and sclerotherapy which involves the injection of medicine into a target varix by a needle passed through the working channel of the endoscope. A further, widely used and increasingly promising technique involves the ligation of lesions, wherein mucosal and submucosal tissue is strangulated by an elastic ligature.
A variety of instruments for effecting the ligation of body tissue by the application of an elastic ring are well known in the prior art. Some of these instruments, because of their rigidity and size, are suited only for treatment of lesions that are in the external regions of the body or in the shallow body cavities. Others are particularly suited for the ligation of tissue in the abdominal cavity, such as for tubal ligation, when the abdominal cavity has been opened surgically.
U.S. Pat. No. 3,760,810 to Van Hoorn discloses an endoscope-equipped instrument comprising a device with two tubes mounted one inside the other, with the inner tube protruding at the front of the outer tube. Means are included to move the outer tube forwardly relative to the inner tube and cause an elastic cord to be dislodged and placed about the tissue to be ligated. In U.S. Pat. No. 4,257,419, there is disclosed an instrument for ligating hemorrhoids, wherein a suction tube fitted inside a proctoscope provides means for sucking the hemorrhoid into a suction cavity where a ligating ring is applied. Both of these instruments are rigid devices suited for treating lesions close to the external regions, and both are equipped with only a single elastic ring for treating a single lesion.
There are also instruments in the prior art which employ laparoscope-assisted means for ring ligation such as shown in U.S. Pat. Nos. 4,257,420 and 4,471,766, wherein the instruments are each equipped with a single elastic band and utilize forceps to position the tissue for ring ligation.
In U.S. Pat. No. 3,870,048, there is disclosed a ring applicator device having forceps slidably mounted in a cylinder for grasping the fallopian tube and including means for displacing an elastic ring to effect a ligation of tissue. While this device can be equipped with a plurality of elastic rings, its rigidity precludes its use with a flexible endoscope for treating the deeper regions of an internal organ, such as the alimentary tract.
A flexible endoscopic instrument used for ligation purposes as disclosed in U.S. Pat. No. 4,735,194, comprises a flexible fiberoptic endoscope to which is secured an outer tube and an inner tube reciprocally movable therein. A trip wire is fastened to the inner tube to provide rearward motion to the inner tube to cause an elastic ring fitted about the inner tube to slide off and effect ligation. While this instrument is suitable for ligating lesions deep within the alimentary tract, it can only be used to treat but one lesion during a single insertion of the instrument.
In many instances, however, there are a number of lesions present in the organ being treated, such as the esophagus, stomach or colon. If an endoscopic instrument equipped with only one elastic ring is used, the treatment of multiple lesions in the same organ requires withdrawal of the endoscope after the placing of each elastic ring about a lesion, reloading the endoscope with a ring, and reinsertion of the endoscope back into the organ to repeat the procedure for placing an elastic ligating ring about each additional lesions. In addition to being time consuming and an associated concern for blood loss when there are bleeding lesions, there are other disadvantages associated with the repetitions of this procedure. The instrument, when withdrawn from the body, is usually covered with blood and mucous. Furthermore, each time the instrument is reinserted into the organ, it becomes necessary to relocate a lesion to be treated and to orient the instrument with respect thereto. In some cases where considerable blood and mucous are present, the relocating of the instrument is a tedious and difficult task.
A flexible endoscopic instrument is provided with a plurality of elastic ligating bands mounted on a barrel of an endoscopic ligator affixed in coaxial relation to the insertion end of an endoscope. The bands are adapted to be dislodged therefrom in sequence at selectively controlled times for treating multiple lesions during a single insertion of the endoscope into a body organ. In one embodiment, the endoscope is equipped with illumination and viewing means to facilitate orientation of the instrument in the body organ, and longitudinally extending tubular passages comprising channels through which objects may be passed and suction applied for drawing lesion tissue into the tubular end of the endoscope to facilitate ligation of the lesion.
The endoscope also includes a working channel through which a flexible actuating cable or trip wire extends. In one embodiment, the trip wire includes a plurality of cords or strands that are free at the insertion end of the endoscope and braided together to form a single strand at the proximal end of the endoscope. In one embodiment, the plurality of strands are each folded over the distal end of the barrel with their respective free ends extending in the longitudinal direction of the barrel and being angularly spaced relative to one another with respect to the axis of the barrel. A plurality of elastic ligating bands are placed in stretched condition about the outside of the barrel at longitudinally spaced locations thereon and over the strands which lay along the barrel.
In one aspect of the invention, each of the strands is provided with a number of beads at predetermined spaced locations thereon and against each of which an elastic band is placed. The strands can be simultaneously retracted by pulling the single braided strand to pull the rings over the distal end of the barrel in controlled sequence. In another aspect, a slack length is provided in the strands between each pair of adjacent elastic rings. In this manner, a small pulling force is required to dislodge any one of the ligating bands from the tube. Accordingly, each of the elastic bands can be dislodged from the endoscope and placed in ligating relation to a lesion when lesion tissue is drawn into the innermost of the tubular members by a suction force applied through the suction channel and each of the bands can be applied to a single or multiple lesions in the body organ during a single insertion of the endoscope.
In a further aspect of the invention, a loading catheter is provided that is adapted for insertion through the working channel of the endoscope. The loading catheter includes loading hooks mounted at opposite ends of a tubular body. The loading hooks are configured to engage a bead or a knot, affixed at the proximal activation end of the trip wire. A hook of the loading catheter can project from the insertion end of the endoscope and working channel and the locking knot of the trip wire engaged in the hook. The loading catheter is withdrawn through the endoscope to pull the trip wire through to the proximal end.
An activating mechanism is provided in one embodiment of the invention to which the trip wire is engaged. In one embodiment, the activating mechanism includes a spool adapted to receive the trip wire, and particularly the locking bead, to permit winding of the trip wire onto the spool. One feature of the invention contemplates a one-way clutch to restrict rotation of the spool to one direction when the trip wire is being retracted to dispense ligating bands. In one specific embodiment, the spool is mounted on a drive pin that is configured with two portions of different diameter disposed within the one-way clutch. One portion has a diameter sufficiently small to permit freewheel rotation of the spool, that is, rotation in either direction. The second portion has a diameter to engage the clutch to limit rotation of the drive pin and spool to a single direction.
Certain benefits of the present invention are realized by a mounting component that is used to mount the activating mechanism to the endoscope. The mounting component can include a stem that is configured to fit within the working channel of the endoscope. The stem is configured to provide a stable mount for the activating mechanism on the endoscope to facilitate operation of the mechanism to dispense ligating bands. In one feature, the activating mechanism and the mounting component can be configured to receive an irrigation adapter to permit irrigation/aspiration of the working channel even when the trip wire is extending and operable therethrough.
One object of the present invention is to provide an endoscopic ligating apparatus that is capable of dispensing multiple pre-loaded ligating bands. A further object is achieved by features of the trip wire that permits a simple, yet effective, construction.
Certain aspects of the invention allow the ligating apparatus to beneficially provide for simple manual operation to dispense a plurality of ligating bands. A further benefit is contemplated by features of the activating mechanism that allows it to be stably mounted to a wide variety of endoscopes.